Roof drain inserts are known such as those taught by U.S. Pat. No. 4,505,499 to Uglow et al, issued Mar. 19, 1985 and U.S. Pat. No. 4,799,713 to Uglow, issued Jan. 24, 1989. Such roof drain inserts are particularly useful in situations where a roof is being resurfaced and a new roof drain is desired to be installed at a height above the existing roof drain. The roof drain inserts have an upper flange for securing to the new roof surface and a tubular member which extends coaxially down inside the existing drain pipe. Since the roof drain insert is received within the drain pipe the horizontal cross-sectional area through which water can flow is reduced in the insert as contrasted with that in the drain pipe.